This might be right in theory but the problem with is is that is how it works for mammals, specifically for humans. If it were the same the fish would be through its anaerobic energy systems within the first thirty seconds when all the ATP and phosphocreatine were used up. The main problem is that fish muscle phys is incredibly different from ours. When ours contract it generates heat, a fishes doesn't so i can't say how it works exactly and you might be right but I think there is a pot more to it than a fish exceeding.g its lactate threshold.